Can maltitol make you fat?

Maybe. You should know that its glycemic index is the highest among all the popular low-calorie sugar substitutes. So it does raise your blood sugar, sorry to say. But it's nowhere close to the GI of sugar.

On the other hand, maybe not.

A gram of maltitol provides 2.1 calories — less than the 2.4 you'd get from a gram of xylitol.

Sucrose (white sugar) has a glycemic index of 100. The other caloric sweeteners are the same, even if they taste a little or a lot sweeter than ordinary white sugar. Agave syrup, honey, maple syrup, fruit juice concentrate — even coconut sugar and dates. All these have the same effect on your blood sugar levels as white sugar.

Some of them, like high-fructose corn syrup and agave syrup (the worst of the bunch) do other damage to your body, by dint of their fructose-heavy composition. But that's a story for another time.

Maltitol's GI, depending on the source, is measured as 36 or even as high as 60. That's quite a bit lower than the 100 of sugar and the rest. However, when you compare it to the other sugar alcohols, it stands outs. Xylitol's GI is reported as 11 or 13. Erythritol's is 0.

Maltitol, erythritol, xylitol. mannitol, sorbitol, lactitol. Notice what these words have in common? The same “ol” at the end as alcohol.

These sweet substances are sugar alcohols — distilled essences of sugar, in a way. Some occur naturally, and others we just invented recently. Even the natural sugar alcohols are made in high-tech ways these days; none of them occur on a large enough scale, historically, for mass cultivation. You'll not find 17th-century woodcuts of long-skirted women gathering baskets full of erythritol under a harvest sun.

Are all sugar alcohols suitable for use as a low-calorie sweetener? Indeed no. Ethylene glycol, for example, definitely will not make you fat. It will just kill you. It's the sweet-tasting ingredient in antifreeze, the reason you have you to keep it locked up safe from children and pets.

Okay, but why do these things get called alcohols? It's a chemical thing. Alcohols are organic compounds where carbon atoms are bonded to OH pairs — a marriage between one oxygen atom and one hydrogen atom, if you will, known as a hydroxyl.

The active ingredient in whisky and wine that we usually just call “alcohol” is only one type of alcohol, of course: ethyl alcohol.

Remember the idea that sugar alcohols are distilled essences of sugar? That fits with the origin of the term “alcohol,” from an old Arabic term for a type of eye makeup made by distilling a certain mineral.

In Arabic, “al-kuḥl” means “the kohl.” The spirit of the soft, gray rock known as antimony.

Eventually, “al-kuḥl” came to signify all kinds of distilled essences, or spirits. It stuck with the spirits we know today as alcohol.

I can't think how to tie this meaningful back to maltitol. But I love the story too much to leave it out. So pretend there's a moral here.

Just remember, like other sugar alcohols used for sweeteners (and not antifreeze or plastics), maltitol is low in calories.

Unlike the rest, it has a GI that's one third that of sugar. Or two-thirds, depending on which lab did the test, I guess.

So if blood sugar is particularly important to you, keep the GI factor in mind. Always, always read food labels. That's important in any case. Look for the presence of maltitol, and adjust your purchase decisions accordingly.

If calories and net carbs are your main concern, you're safe just reading the numbers provided on the Nutrition Facts label. Maltitol has one of the most neutral tastes of all the low-cal sweeteners, and so if it's the only one listed on the label, you're likely to be in for a treat.